1. Field of the Invention
The present invention relates to an image forming method.
2. Description of the Related Art
In recent years, as a result of the progress in inkjet recording technologies, there have been suggested image forming technologies utilizing an inkjet method as a method of forming high definition images for photograph applications or offset printing applications. In the inkjet method, it is required that high quality images can be formed at a high speed.
More recently, the demand for image forming at a high speed is further increasing. For example, in a system of drawing an image at a high speed using rolled paper, scratch resistance after drawing is important. That is, if the scratch resistance of an image is low, after an image is drawn, the rolled paper on which an image was drawn is piled up for a short period of time, and when paper sheets are brought into contact and rubbed with each other, blurring or the like may occur in the image, so that the product value may be lost in some cases.
Specifically, if the scratch resistance of a drawn image is poor, a trouble occurs such that when a character image is drawn, the character may become faint, and when dropout characters are drawn, the characters cannot be read. Furthermore, when an image of a bar code or a QR code (registered trademark) is drawn, a trouble that the code may not be normally read may occur. Such a phenomenon is significantly likely to occur, particularly in paper in which an ink can be easily retained on the paper surface, for example, paper exclusively for inkjet printing that does not have a porous ink-receiving layer.
Meanwhile, there is a technology of improving ink penetrability into paper as an ink technology. In this case, an ink easily penetrates into paper. Therefore, the scratch resistance of the image itself is improved. However, optical density (OD) deteriorates and a phenomenon (strike through) in which an ink passes through paper and seeps through a rear surface of the paper is significantly shown. For this reason, as a result, there is a problem in that it is impossible to draw images on both surfaces by simply improving ink penetrability. In addition, there is also a problem in that, when drawing an image using multiple colors such as red, green, and blue, color inks spread on paper and are mixed together, and therefore, a color gamut of the secondary color is degraded. Such a phenomenon is likely to occur significantly, particularly in paper in which an ink easily penetrates, for example, plain paper.
Attention is paid to water-based inks as an ink used in inkjet methods in view of considering the environment. For example, from the viewpoints of ejection stability of the ink, and print quality such as less bleeding on plain paper, aqueous inks containing ethylene oxide adducts or propylene oxide adducts of glycerin have been disclosed (see, for example, JP2009-191135A).
In addition, as an ink set which can suppress occurrence of ink bleeding and color mixing in an image while suppressing occurrence of curling and wrinkles called cockling in recording, an ink set which contains an ink composition containing a colorant, resin particles, a water-soluble organic solvent, and water; and an aggregating agent for aggregating components in the ink composition; and a treatment liquid containing a water-soluble polymer which does not cause aggregation of the components in the ink composition is known (see, for example, JP2010-023339A).